Explanation:
Let us calculate the work done in lifting an object of mass m through a height h, such as in Figure 1. If the object is lifted straight up at constant speed, then the force needed to lift it is equal to its weight mg. The work done on the mass is then W = Fd = mgh. We define this to be the gravitational potential energy (PEg) put into (or gained by) the object-Earth system. This energy is associated with the state of separation between two objects that attract each other by the gravitational force
Potential energy is a property of a system rather than of a single object—due to its physical position. An object’s gravitational potential is due to its position relative to the surroundings within the Earth-object system. The force applied to the object is an external force, from outside the system. When it does positive work it increases the gravitational potential energy of the system. Because gravitational potential energy depends on relative position, we need a reference level at which to set the potential energy equal to 0. We usually choose this point to be Earth’s surface, but this point is arbitrary; what is important is the difference in gravitational potential energy, because this difference is what relates to the work done. The difference in gravitational potential energy of an object (in the Earth-object system) between two rungs of a ladder will be the same for the first two rungs as for the last two rungs.
The mass of the second car is 1434.21 kg
<u>Explanation:</u>
Using law of conservation of momentum,

Given:
= 1090 kg
= 11 m/s
= 0
v = 4.75 m/s
We need to find 
When substituting the given values in the above equation, we get





Constructive interference of two coherent waves will occur if the path difference is λ/2.
<h3>Constructive interference:</h3>
When two waves are in phase and their maxima add, a process known as constructive interference occurs where the combined amplitude of the two waves equals the sum of their individual amplitudes.
The resultant wave is created by adding the amplitudes of two waves that are in phase and traveling in the same direction. The waves in this instance are said to have experienced beneficial interference. The upward displacement of the medium is higher than the displacement of the two interfering pulses because upward displacement occurs when the waves experience constructive interference. When the phase difference between the waves is an even multiple of (180°), constructive interference happens.
Learn more about constructive interference here:
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1. becuase it is so hot that it could tan or be used to keep warm.